Polymer precursor synthesis and characterization ofYBa2Cu3O7−x

We report the synthesis of $\mathrm{Y}{\mathrm{Ba}}_2{\mathrm{Cu}}_3{\mathrm{O}}_{7-x}$ prepared by a polymer precursor route. Polycrystalline single-phase materials have been produced in a porous morphology. The technique is also used to create fibers with diameters as small as several μm. The resistivity transitions are shown to be sharp with transition widths narrower than 1 K. Conductance fluctuations are measured in the vicinity of the superconducting transition and are consistent with three-dimensional superconductivity in the polycrystalline materials.